1. Field of the Invention
The present invention relates to a wideband antenna for receiving digital TV signals, and more particularly to a digital TV antenna with a wideband characteristic and the antenna can easily be adjusted.
2. Description of Related Art
In the recent, the application of mobile media device is increasing. For example, the digital TV is widely used for providing user various functions. The car receiving system is used for presenting digital TV in cars to passengers. Home users can watch sport programs any time or choose a program by the VOD system (Video On Demand). Conventional receiving apparatus of digital TV usually has a receiving antenna for receiving the signals of digital TV programs. For example, a monopole antenna of metal rod can be used in the USB TV-tuner dongle.
The height of the monopole antenna of metal rod is about 13 to 17 cm and the monopole antenna has a transmission line. The length of the transmission line is about 100 to 150 cm. However, the above-mentioned antenna is a narrow-band antenna and the impedance bandwidth of the antenna is about 100 to 200 MHz only. The bandwidth of the antenna cannot cover the wider band, such as digital TV frequency band of 470 to 862 MHz. Thus, the conventional narrow-band antenna cannot provide good performance in the area with low signal strength of the digital TV programs.
On the other hand, the exterior antenna for receiving digital TV signals further includes a planar dipole antenna. The bandwidth of the antenna cannot entirely cover the frequency band of the digital TV. Furthermore, because the antenna is fixed, the end user has to move the whole device for adjusting the position and angle of the antenna in order to receive signals with better quality. In other words, it is not convenient for the end user to adjust the antenna in the practice.
Hence, the inventors of the present invention believe that the shortcomings described above are able to be improved and finally suggest the present invention which is of a reasonable design and is an effective improvement based on deep research and thought.